1. Field of the Invention
The present invention relates to a marking method suitable for marking a chassis number to a body, for example, a body of a motorcycle and a marking apparatus.
2. Description of Related Art
Conventionally, as a method of marking a chassis number to a body of an automotive vehicle which is conveyed on an assembly line, for example, there has been known a technique described in Japanese Patent Examined Publication No. 61-49152.
In this technique, a label having coded information concerning a vehicle type, a vehicle number, an operation command and the like is attached to a vehicle body moving on an assembly line, and information necessary in each of the stations is read out by a bar code reader so that various kinds of operations are performed. In this technique, when a chassis number is marked on the vehicle chassis, a vehicle number is read out from the label by the bar code reader, the read-out data is transmitted to a marking apparatus through a control apparatus so as to set the marking apparatus in a state capable of marking the chassis number, and the set number is returned to the control apparatus so as to compare with the read-out data by the bar code reader, then the marking operation is performed.
However, in the above method, there is a possibility that an erroneous signal is read out by the bar code reader, and further there is a possibility that when the read-out signal is transmitted to the controller, the right data is not transmitted as an electric signal, so that it is not secured that the marking is performed on the basis of the complete right data.
On the contrary, there is a case that such a chassis number is marked as a dot character and the like by a dot marking apparatus, and further, there is a case that after marking to the vehicle body, in order to confirm whether or not the marking is performed in a suitable state, an inspection is performed by an optical sensor and the like. At this time, in order to solve a trouble that a defect is erroneously judged due to a slight difference as judged by viewing, for example, a technique is disclosed in Japanese Patent Unexamined Publication No. 8-138049 has been known.
In this technique, it is structured such that the dot character or the like as a subject to be inspected is read out and the read-out character or the like is compared with a normal character or the like pattern previously stored or a dot cancel character or the like pattern which is formed by canceling some dots from the normal character or the like pattern, so that when a predetermined rate of concordance is obtained, the dot character or the like is judged to be normal.
However, in the case of the above technique, a judgment whether good or no good is performed by simply comparing the measured character pattern with the standard character pattern and an effect of the measuring error and the like is not taken into consideration, so that in the case that the measuring error is great, there is a great possibility of performing an erroneous judgment.
Further, since a sound is generated when the chassis number or the like is marked, for example, on a metal frame or the like by this kind of marking apparatus, in order to prevent the sound, a method of marking the number while shutting a sound within an isolation chamber and the like is generally employed.
Still further, in this kind of marking apparatus, it is structured such that a door or the like which is freely opened and closed is provided in the isolation chamber or the like, and after opening the door or the like, the work is taken in and out by using a slide mechanism or the like, thereby performing the marking.
However, in the isolation chamber or the like mentioned above, at least two kinds of actuators consisting of an actuator for opening and closing the door or the like and an actuator for taking the work in and out are required, and an operation of taking the work in and out and an operation of opening and closing the door or the like are separately performed, so that there is a problem that a time loss is produced.